| Term | Definition |
| Mannitol Salt Agar (MSA) | Selective for: salt tolerance (staphylococcus)
- Growth = Staphylococcus
- NO growth = not Staphylococcus
Differential for: Mannitol fermentaion
- agar turns yellow = ferments mannitol
- no color change = negative for mannitol fermentaion. |
| Selective Media | Inhibits certain organisms and encourages others to grow well |
| Differential Media | Indicators expose differences between organisms. Bacteria will grow different colors. |
| Catalase Test | -Breaks H2O2 into H2O and O2
+ results if bubbles when H2O2 mixed with bacteria.
Differentiates b/w Staphylococcus and Streptococcus.
- Staph - is positive
- Strep - is negative
An enzyme found in aerobes, microaerophiles and facultative anaerobes. |
| Coagulase Test (StaphTex Kit) | Differential for Staphylococcus vs. other staphylococci species
+ results: Blue clumping after addition of solution to bacteria w/in 5-10 sec. Coagulase and protein A present.
+ result = S aureus
- result = S epidermitis |
| Streptococcus Organisms Latex Agglutination (StrepPro Grouping kit) | Differential for B-hemolytic streptococci sprecies.
+ result: blue clumping after bacteria mixed with solution.
- Lancefield serological grougings - Group A, B, C, D, F OR G Strep |
| Cardinal Temperature | The minimum, optimum and max temps bacteria will grow. |
| Optimum Temperature | The tempurature at which the growth rate is the HIGHEST. |
| Psychrophiles | Temps of - 30deg C or below |
| Psychrotrophs | Temps - 0-30deg C |
| Mesophiles | Temps - 15-45deg C
- MOST PATHOGENS |
| Thermophiles | Temps - Above 40deg C |
| Extreme Thermophiles | Temps - 65-110deg C |
| Acidophiles | Grow well below pH 5.5 |
| Neutrophiles | Prefer pH b/w 5.5-8.5
MOST PATHOGENS!
*Bacteria maintain an internal pH near neutral |
| Alkaliphiles | Live about pH 8.5 |
| UV Radiation (Electromagnetic Radiation) | - Kills bacteria by damaging the DNA
- Specifically THYMINE DIMERS
- Once enough genes are damaged the bacteria cannot survive. Longer exposure kills more.
*E coli - not UV tolerant
*Bacillus subtilis (in soil) - more UV tolerant and endospore former. |
| Anaerobic Jar | Agar plates placed in special container and placed in incubator.
-Chemicals in packet inside jar use up all the free oxygen and make an ANAEROBIC environment
*Obligate aerobes will not be able to grow. |
| Antiseptics | Removes vegetative pathogens from LIVING TISSUE.
DOES NOT KILL ENDOSPORES!!! |
| Obligate Aerobes | REQIURES OXYGEN to grow |
| Facultative Anaerobe | Grows BETTER with oxygen, but can live without |
| Obligate Anaerobe | CAN'T tolerate O2 and will NOT GROW when present. |
| Microaerophiles | Grows best in REDUCED OXYGEN environments |
| Aerotolerant Anaerobes | Doesn't use oxygen to grow, but they tolerate it without adverse effects |
| Superoxide dismutase | an enzyme used to neutralize negatively charged oxygen molecules (O2-) called superoxide radicals. Those molecules are produced when many organisms produce ATP. Superoxide dismutase converts these molecules to Hydrogen peroxide (H2O2). |
| Catalase | an enzyme that converts hydrogen peroxide to water and molecular oxygen (O2). |
| Peroxidase | an enzyme that converts hydrogen peroxide to water without making molecular oxygen. |
| Disinfectant | Chemical that destroys vegetative pathogens. WILL NOT KILL ENDOSPORES!
- To be used on surfaces not people |
| Sterilization | The highest level of microbial control. Kills ALL forms of microbial life including endosopores. |
| Commercial sterilization | Heat treatment strong enough to kill endospores of Clostridium botulism.
- used in canning indusrty. |
| Germicides | Chemicals that kill microbes |
| Bactericidal | Chemicals kill bacteria but not other microbes |
| Bacteriostatic | Keep bacteria from growing.
- do NOT actually kill the bacteria |
| Nonionizing radiation | - Weaker type of radiation
- UV light - damages the nucleic acids. Causes Thymine dimers.
- Bactericidal
- Used for disinfecting surfaces, air and drinking water. |
| Ionizing radiation | - Stronger type
- Xray and gamma rays
- cause breaks in the DNA backbone and damage
cell membranes
- Can pass thru packaging - sterilize surgical instruments in wrappers
- Eliminates pathogens in food. |
| Enterotube II | Used for identification of enteric bacteria
* Found in the gut
- Gram negative
- Bacilli
- MUST BE OXIDASE NEGATIVE!
* Would use patients stool sample to perform test. |
| Blood Agar | Differential hemolysis of RBC's
- Gamma= no hemolysis (enterococcus)
- Alpha= green color, partial hemolysis (norma flora)
- Beta= Clear, complete (Group A Strep)
*Hemolysis occurs due to EXOTOXINS called HEMOLYSINS.
hemolytic Gram + cocci PATHOGENS |
| Epidemic | More than expected cases of particular disease in specific area. |
| Endemic | A disease or condition regularly found among particular people or in a certain area. |
| Pandemic | A disease prevalent in more than one continent. |
| Heard immunity | *VACCINATE MOST TO PROTECT ALL
-General immunity to a pathogen in a population based on the acquired immunity to it by a high proportion of members over time. |
| Morbidity | Number of people with a disease in a population |
| Mortality Rate | Incidence of death in a population during a specified time interval. |
| Incidence | the rate at which new cases occur in a population during a specified period |
| Reservoir of infection | Any person, animal, plant, soil or substance in which an infectious agent normally lives and multiplies. |
| Portals of entry | a pathway into the host that gives an agent access to tissue that will allow it to multiply or act.
- use the same portal to enter a new host that they used to exit the source host. |
| Epidemiology/Epidemiologist | Investigate disease outbreaks to determine:
- Causative agent
- Reservoir
- Route of Transmission
*Allows them to recommend ways to minimize spread. |
| MMWR Report | -Morbidity and Mortality Weekly Report.
-Prepared by the CDC every week
Monitors infectious diseases throughout country
-Based on weekly reports from the state health departments of reportable diseases. |
| Prevalence | the proportion of a population that is affected by the disease at a specific time |
| Propagated epidemic | Transmission of disease from one person to another thru direct contact, vehicleborne (sharing needles), vecotrborne (mosquito bite).
Cases occur over more than one incubation period |
| Common source epidemic | When a group are all exposed to an infectious agent or a toxin from the same source.
- Number of cases spikes quickly and then drops quickly.
*Contaminated drinking water |
| Fomites | any inanimate object that can carry disease-causing organisms. |
| Incidence Rate | a measure of frequency of new cases of illness expressed per a time frame.
-calculated as the number of new cases over a specified period divided either by the average population or by the cumulative person-time the population was at risk. |
| Index Case | The first case or instance of a patient coming to the attention of health authorities. |
| Communicable disease | Disease directly or indirectly transmitted from man to man, from animal to man, from animal to animal, or from the environment (through air, water, food, etc..) to man |
| Contagious disease | Disease transmitted through contact.
- Scabies, STD's |
| Portals of Exit | a pathway by which an agent can leave its host.
- usually corresponds to the site where the pathogen is localized
* influenza exits via resp tract |
| Modes of transmission | Infectious agent transmitted to susceptible host by:
-Direct = Direct contact, Droplet spread
-Indirect = Airborne, Vehicleborne and Vectorborne |
| Infectious diseases | Caused by pathogenic microorganisms.
-can be spread, directly or indirectly, from one person to another |
| Non-Communicable disease/Non-Infectious diseases | Chronic diseases not passed from person to person. Can be genetic.
Long duration and generally slow progression.
4 main types:
-Cardiovascular
-Cancer
-Chronic Respiratory
-Diabetes |
| Zoonosis | An infection that is transmissible under natural conditions from vertebrate animals to man
- Rabies, Plague |
| Opportunistic infection | Organisms that take the opportunity provided by a defect in host defense or immunity to infect the host. |
| Decontamination | The removal or neutralization of a contaminating substance, such as poisonous gas or a radioactive material. |
| Vegetative Cell | An actively metabolizing cell. |
| Spore | A dormant, reproductive cell formed by certain organisms.
-It is thick-walled and highly resistant to survive under unfavorable conditions so that when conditions revert to being suitable it gives rise to a new individual |
| Direct ELISA | Uses known antibodies attached to wells to detect the presence of particular antigen. |
| Indirect ELISA | Used to determine the presence of specific antibody (HIV antibody) in serum. |
| Antimicrobial Susceptibility | Kirby-Bauer Method Disk Assay. Start with MacFarland Tube for proper turbidity.
- Measure Zone of Inhibition (diameter in mm) for each ATB and compare to chart. |
| Eukaryotic Organisms | Categories: Helminth, Protist or Fungus
- Can be pathogenic or non-pathogenic
*Similar to human cells. |
| Non-Pathogenic Protozoans | Mixed Green Algae
Mixed Diatoms
Spirogyra (an algae) |
| Mixed Green Algae | Photosynthetic
Are all GREEN from Chloroplasts
Have a nuclei |
| Mixed Diatoms | Are MULTI-COLORED with glassy/silica shell
Used in making glass and whitening toothpaste |
| Spirogyra (an algae) | Non-pathogenic
Have nucleus |
| Pathogenic Protozoans | -Two forms: Cysts and Trophozites
Entamoeba histolytica
Balantidium coli
Giardia lamblia
Plasmodium falciparum
Plasmodium vivax
Trichomonas vaginalis
Tryanosoma gambiense |
| Entamoeba histolytica | *Amoebic dysentary, bloody diarrhea |
| Balantidium coli | *Intestinal disease
- Has nucleus and cyst wall |
| Giardia lamblia | *Giardiasis - Treated with Flagyl
Through contaminated drinking water.
- Heart shaped with 2 nuclei and flagella
- Has protective shell
Can survive outside body for long periods of time.
Resistant to UV radiation |
| Plasmodium falciparum | * Malaria
- Obligate INTRACELLULAR PARASITE - has to reproduce inside host cell
- Infection of RBC's
Vector is Anopheles mosquito |
| Plasmodium vivax | * Recurring Malaria
- Rapid division in Liver
Transmitted by vector - Mosquito |
| Trichomonas vaginalis | *Trichomoniasis
Very common
- Can be STD or from improper wiping and hygeine
- has an undulating membrane with many flagells. |
| Tryanosoma gambiense | * African Sleeping Sickness
- Extracellular - not inside RBC, just in blood
Vector - Tsetse fly |
| Pathogenic Fungi | Have chitin cell walls
- Dimorphic (2 shapes): YEAST (CIRCULAR) AND MOLD (LONG/TUBULAR)
Aspergillis
Rhizopus (Bread mold)
Penicillium
Candida albicans
Pneumocystis carinii |
| Aspergillis | * Aspergillosis - Can be dangerous in people with compromised immune system.
VERY COMMON - no harmful in healthy people |
| Rhizopus (Bread mold) | * Bread mold
* Zygomycosis in diabetics and immunocompromised patients.
Has GOLD spores
Rhizoid shape |
| Penicillium | - NON-PATHOGENIC
Paint brush like shape
* Opportunistic infections in: Lungs, Liver and Skin in immunocompromised patients.
- What antibiotic Penicillin original discovered in. |
| Candida albicans | * Yeast infections, Thrush
Normal flora in resp, GI and female GU
-Dimorphic - Yeast and filamentous (Hyphae) forms
-Opportunistic pathogen
Common in: Diabetics, patients with foley, on anti-microbials and immunosuppressed. |
| Parasitic Helminths | *Roundworms, Tapeworms (Cestodes) & Flatworms (Flukes)
Trichuris trichuria (Roundworms)
Enterobius vermicularis (Pinworms)
Schistosoma mansoni
Taenia pisiformis (Tapeworms)
Trichinella spiralis (Roundworms) |
| Enterobius vermicularis (Pinworms) | * Human pathogen
Eggs found in stool or around anus
- "Scotch tape" method to anus to detect. |
| Schistosoma mansoni | * Parasitic and found in LIVER AND INTESTINES |
| Taenia pisiformis (Tapeworms) | - Body divided into segments called proglottids. Each segment has reproductive parts.
- Head called SCOLEX and has suckers and hooks to latch on to host.
-Hermaphrodites |
| Trichinella spiralis (Roundworms) | * Trichinosis
- Encysted roundworms in muscle tissue.
Used to be what made pork not kosher and unable to eat. |
| Arthropod (Insect) Vectors | Mosquitos
Human Louse
Deer Fly
Ixodes dammini |
| Mosquitos | * Transmits MALARIA |
| Human Louse | * Transmits PLAGUE |
| Deer Fly | * LYME DISEASE |
| Ixodes dammini | * LYME DISEASE
- Deer Tick |
| Pneumocystis carinii | * Pneumocystis carinii Pneumonia (PCP)
- Opportunistic pathogen in AIDS
Grows in lungs and adheres to alveolar cells. Inhibits gas exchange
- Hard to treat |
